1. Field of the Invention
This invention relates to a wireless network device provided with a signal detection function and method of switching for the same, and more particularly to a switching determination with a load voltage of the wireless network device, a versatile networking device detecting signals thereby being formed.
2. Description of Related Art
Thanks to a public wireless network gradually being created everywhere, users have increasing chances to use wireless local area network (WLAN) in public places. Users do not, however, actually carry out wireless networking at all times, everywhere. They must turn on devices provided with a wireless networking function, such as, for example, a PDA or a portable computer, to determine whether a wireless network signal is present through a wireless network utility working with an internal or external wireless network device prior to use of the wireless networking service.
A general external wireless network device, as shown in U.S. Pat. No. 6,633,583, is a wireless communication receiver using a universal serial bus (USB) as an interface, in which a signal conversion circuit is used to convert a wireless signal received from an RF module into a signal based on USB protocol, or convert and transfer a digital signal based on USB protocol to the RF module, and then send out the signal through an antenna.
As shown in FIG. 1, a wireless device connected to a PC host 16 through a USB host interface 14 is disclosed in U.S. Pat. No. 6,782,245. The wireless device is structured with an antenna 11 receiving and transmitting signals and connected to a receiver 12 for converting the signals according to the frequency of received signals into digital signals. The signals are then transmitted to a microcontroller unit 13 for decoding the signals and debugging, and next converting the signals into USB-based signals transmitted to the PC host 16 through the host interface 14. All the above devices are supplied with electric power by a power supply 15.
However, in view of the single function and structure provided in the wireless module and the lack of a full layout of wireless network, it is complicated and inefficient to detect the network signals.